Why Does Breast Cancer Kill More Black Women?

Black and white women get breast cancer at about the same rate, but we are more likely to die from it. This isn’t new information; it’s been this way for years, worsening over time. In fact, by 2012, death rates in black women were 42 percent higher than those in white women.

The disparity has researchers puzzling over one question: Why?

A woman’s biology—and lifestyle factors such as physical activity and being sedentary—all play a role, said Cher Dallal, an assistant professor at the University of Maryland’s School of Public Health.

But “there has been little research done in this area,” she said, “particularly among black breast cancer survivors.”

It’s why she’s studying biobehavioral links, the relationship between a woman’s activity level and her biological makeup, and focusing on how these connections play out in white women and black women who have survived breast cancer.

With support from a five-year American Cancer Society grant, Dallal is currently recruiting 100 black and white breast cancer survivors. For seven days, the recruits will wear a Fitbit-style device to measure how much they move and how often they are couch potatoes. They will also provide blood samples, which Dallal will analyze to look for differences in molecules involved in key biological processes and which give a snapshot of overall health. This is known as metabolomic information.

Dallal’s mission: to find out if higher levels of physical activity among breast cancer survivors are associated with differences in their metabolomic information, with an emphasis on the potential differences in these associations between black and white breast cancer survivors.

“Once we have this data, we’ll start looking for patterns,” Dallal said. “In addition to the metabolomics data, accelerometers allow us to measure a range of physical activity, including light and moderate activities. We’ll be able to look at time spent in active and sedentary behaviors and how these behaviors may be associated with various metabolites across multiple biological pathways.”

If, for example, Dallal and her team find breast cancer survivors are more likely to walk—and this type of activity is associated with more favorable metabolomic information—it could help develop strategies for improving breast cancer survival.

The researchers will also gather data about participants’ socioeconomic status, where they live, their weight and their diet, as well as information about tumor type.

“With this information, our hope is that we will better understand physical activity and sedentary behaviors among breast cancer survivors and whether these behaviors influence biological profiles,” she said. “From there, we can inform strategies to help breast cancer survivors improve their prognosis and ultimately to reduce the observed racial differences in breast cancer survival.”